A vigilance monitoring system to determine the alertness of a driver of a vehicle. The system uses one or multiple sensors located at the driver-vehicle interface (steering wheel, accelerator, brakes). The sensor monitors the magnitude and frequency of the force (or displacement) exerted by a driver at the driver interface. A time derivative of the force or displacement profile is created. The variability of the time derivative of the force/displacement data from the general trend of the data as obtained by an optimized moving average of the data. An intelligent control system measures the variability and compares with an alertness rating scale to determine the alertness score of the driver and issue warning signals and actions as appropriate.